From Old Japanese. Originally a compound of 神 (kamu, “spirit, god”) +‎ 座 (kura, “seat”).[1][2][3] The kura changes to gura due to rendaku (連濁). The original compound referred to the place used to call down the 神 (kami, “spirits and gods”) to earth, when a 巫女 (miko, “shrinemaiden”) would act as a medium for the kami. Over time, the term came to refer to the music and dance of the ceremony. The use of the 楽 character here is an example of ateji, reflecting the change in meaning.